Tool coupling assembly



his:

T. N. SHlGEKUNl 3,023,054

TOOL COUPLING ASSEMBLY Feb. 27, 1962 Filed June 15, 1960 INVENTOR. T HUM/7S Al. JH/GEKUN/ l l l nit 3,023,054 TOOL COUPLING ASSEMBLY Thomas N. Shigekuni, 1111 E. Rosencrans Ave, Gardens 59, Calif. Filed June 15, 1960, Ser. No. 36,416 11 Claims. (Cl. 30631) This invention relates to an improved coupling construction for quick attachment and detachment of various tool heads on a single handle, or alternately for replacing or substituting successive handles on such a work head, thus permitting the more efiicient use of various tool elements by reason of the interchangeability imparted to them. The present construction is particularly exemplified by horticultural or garden tools which by hand operation receive heavy shocks or vibration, such as hoes, rakes, weeders, cultivators, edgers, and the like, which may now have their respective operating heads interchangeably mounted on a handle with the coupling mech anism here described. However, other tool elements or work heads which are not subject to such strain in use can advantageously employ the present construction as well.

The invention is especially adapted for coupling wooden handles with metallic tool heads or more specifically with work heads having metallic attachment shanks of tubular form into which the wooden handle is inserted. Typically a woodenhandle used with outdoor hand tools, in addition to the very considerable mechanical buffeting suffered in actual use, experiences an accelerated amount of aging and disintegration due to necessary or accidental exposure to conditions of moisture arising from weather and irrigation, from contact with reactive chemicals used in treating plants and soil, from attacks by lower organisms such as dry rot, termites, etc. so that the critical handle section within the attachment band or socket of the tool too often quickly becomes a misfit by reason of warping, splitting, shrinkage or disintegration. Then subsequent attempts to tighten the head mounting by inserting of shims orstaples in the socket area afford but fleeting adjustment because the non-uniform engagement between handle and socket and/or further splitting the wooden handle and consequently promoting greater disintegration thereof. While obviously cylindrical or conical handle ends might be preferred because of forming a better initial fit, in contrast oval or rectangular socket sections have often been used because-the actual coupling 1 means employed did not prevent the conical handle from turning in the socket after a little use. And of course such looseness wasfrequently the forerunner of subsequent separation or breakage between the tool head and handle. Consequently, efforts to further tighten the engaging portions of handle and head usually destroyed any latent or potential possibility of making such units interchangeable, with the practical result that if either the handle or head were damaged, the entire assembly had to be replaced.

Consequently it is an important object of the invention both to retard or minimize the localized wear and disintegration of the wooden handle at the attachment area, and at the same time to provide coupling means which compensate for such variation of dimension so as to lengthen the eflective life of the handle. Another purpose is to provide an adjustability which is still compatible with maintaining a snug fit in the coupling assembly whereby handles or tool sockets of somewhat. different or non-identical dimensionswhether initially present or brought about by use and age-can accommodate each other. Thus, if the diameter of a conical attachment end of a handle has shrunk or otherwise diminished, it

can still be firmly secured after inserting it farther into 3,fl23,54 Patented Feb. 27, 1962 the socket and locking it at a new position. Or considered another way, the tool socket and corresponding handle end do not have to be made to such close precision initially in order for corresponding units to be used interchangeably.

Still another advantage is obtained by effecting these results in such manner that even when the handle becomes loosened in the socket, the tool head does not immediately fly off or separate, but upon the operator observing the loose condition, the coupling can readily be tightened, in a new position if necessary, in a moment of time. In other words, more than a minimalor initial looseness is necessary to permit disengagement of the handle and socket, and such condition usually attracts the attention of the operator in time to correct it. It can also be guarded against in the present construction by addition of a lock nut or similar element.

Yet another object is to provide such a quick coupling assembly wherein the several coupling elements can be connected together in different combinations, the composite construction varying initially with whether the headed bolt is inserted through its aperture from one side or the other, and secondly varying with whether or not an extra locking effect is desired. In addition, the coupled assembly has the advantage of employing conventional elements such as a headed bolt, a square nut, and optionally a wing nut, the particular advantage here arising from the useof these elements in the mounting provided by the fitted handle and socket member.

A further purpose resides in effecting such an interchangeable coupling assembly wherein each of the conical socket and the inserted cone are directly engaged by an opposing coupling element carried respectively by opposite ends of the bolt; thus the headed end of a coupling bolt seats against the outer face of the metallic socket tube while another locking or anchoring element carried by the other end of the bolt seats directly against the wooden handle within a positioning socket provided in the adjacent tube wall (or vice versa), the metallic tube and wooden handle respectively forming part of the tool head or operating handle as the. case may be.-

A particular feature of such construction is based on provision of an essentially polygonal shaped opening formed in the metal tube to serve as a socket for the anchoring element of the coupling assembly, which elementexemplified either by a square head or a square nut on the mounting boltby reason of being jointly seated therein and in an adjacent angular socket of the wooden handle, anchors the (still rotatable) bolt against movement independent of the tool head while permitting (While loose') limited longitudinal adjustment along'the attachment cone of the handle so as to enable tightening or locking the coupling unit at an ultimate position of snug engagement between the metal attachment tube (of the tool head) and the handle cone inserted therein, such longitudinal adjustment. being possible because of an elongated bolt-carrying aperture in the.cone.

In this connection, an especially advantageous coupling is obtained by augmenting the initial conical insert and socket attachment of the present coupling elements by a particular notch construction ofthe handle cone whereby an attempted disengagement ofthe coupled cone and socket. is opposed by a progressively increasing wedge action of the inserted handle end against the coupling and locking elements which are anchored to the socket member. This action is opposite the conical fit of the handle in the tubular socket and is achieved by reason of the transverse planes of the handle cone defined by opposite ends of its bolt-carrying aperture being inclined convergingly toward the free end of the handle and away from the socket.

Additional objects and advantages will become apparent as the description proceeds, particular reference being made to the illustrated embodiment of the invention wherein FIGURE 1 is a side elevational view of a hoe having the tool head and handle detachably coupled together according to the present invention;

FIGURE 2 is a fragmentary side elevational view of a half-moon-edger tool head detachably coupled to the same handle;

FIGURE 3 is a side elevational view of the handle attachment end and connected tool head socket, partially in longitudinal section to show the elements of the coupling assembly;

FIGURE 4 is a longitudinal sectional view, partly in elevation, of the attachment end of the handle out of the socket;

FIGURE 5 is a fragmentary, top plan view of the attachment end of the handle as seen along the line 55 of FIGURE 4;

FIGURE 6 is a similar view to FIGURE 3 but with the elements of the coupling assembly connected together differently;

FIGURE 7 is a fragmental, top plan view of the mounted socket member particularly showing the seating of the anchoring member in the square opening thereof as viewed along the line 7-7 of FIGURE 6;

FIGURE 8 is a fragmental sectional view along the line 8-8 of FIGURE 3 particularly showing the curvature of the washer, and

FIGURE 9 is a construction detail of an assembly similar to FIGURE 6, but showing in elevation a headed bolt having an integral nut-shaped portion forming part of the head.

As here depicted, there is provided a metallic tool head, such as a hoe 10 or lawn edger 12, detachably coupled to an elongated, generally straight, cylindrical handle 14, conveniently made of wood and especially, in the case of garden tools, being of sufficient length to provide hand holds for both hands of the user intermediate its length so that he can move the tool head at the ground level without necessarily bending his back. For attachment, the lower end of the woden handle is conically shaped 16, radially decreasing terminally toward a theoretical point, in practice being frusto-conical. Such attachment end is thus adapted for relatively snug, frictional engagement' upon insertion within a correspondingly shaped, open-topped, tubular socket 18 which projects upward from a central shank 20 of the work head.

For coupling, the attachment end of the handle is formed with a transverse aperture 22 generally intersecting the cylindrical axis of the handle and inclined from a radial or perpendicular plane so that its respective end openings lie at dilferent transverse levels, that is, are

longitudinally staggered, along the attachment cone 16.

In addition, the aperture 22 is elongated in the direction of the handle axis so as to be approximately elliptical gated opening 30 in alignment with the similar aperture opening 24. To provide for the wedging resistance to Withdrawal of the engaged handle noted above, the planes of the opposite ends of the transverse aperture 22 should;

be non-parallel and disposed convergingly toward the free end of the handle-that is, opening or diverging in the direction of the socket 18 so as to define a wedge. In

other words, the distance a should be greater than the :distance b, FIGURE 4. t

The tubular socket member 18'of the tool head, adj'acent its upper margin is formed with a diametrically opposing pair of dissimilar openings, spaced to align with the respective staggered ends of the cone aperture 22, the lower opening 32 being circular so as to receive the cylindrical shaft of a bolt theret-hrough, and the upper opening 34 being approximately square (FIGURE 7), or in any event having angularly intersecting edge walls or corners 34 adapted to engage or receive therein corresponding corners or side walls of a polygonal not or bolt head (as hereafter described). Due to the conical curvature of the tube 18, as well as the angle of inclination of the slideway 27, the opening 34 for accommodating a square nut or bolt head is not exactly square, but its transverse edges which slidingly register with the adjacent end of the bolt are curved or bowed, as seen in FIGURE 7.

The coupling elements employed for detachably joining the attachment cone 16 and tubular socket 18 are three or four in number, depending upon whether an extra locking action is desired, in which latter case an additional, threaded (wing) nut is employed. In assembly, the conical tubular socket 18 is slid over the frustroconical plug 16 until its forward edge 38 (optimally) abuts against the terminal shoulder 40 of the cone 16, with the square aperture 34 of the socket member aligned with the base plate 28 or notch floor 27 immediately beneath. In such position the cone 16 desirably fits snugly within the conical socket 18, sometimes before the edge 38 of the tube reaches the abutment shoulder 40.

On the oppositeside of the unit, the round opening 32 of the tube is then in line with the corresponding end of the slanted aperture 22 of the cone.

Accordingly, a terminally threaded bolt 42 carrying a wedge-shaped washer 44 under its head is then inserted through the round opening 22, and its free end upon projecting from the other side of the cone 16 is screwed into a threaded nut 46 (FIGURE 3) which is held upon the base plate 28 or supoprting surface 27 of the notch. The nut 46, perpendicular with relation to its mounting bolt but angularly inclined relative to the socket opening 34, is thus restrained against rotation by its sliding fit within the socket. On the opposite side of the tube, the washer 44, having the general configuration of an annulus or eyelet, is formed with a curved or arcnate underface 50- corresponding to the external curvature of the tube wall 18 with which it is disposed in frictional registration. A flat, annular top area 52 about the washer opening forms a seat for tight frictional engagement with the perpendicular underface 54 of the bolt head 56, or with the corresponding engaging surface 58 of a wing nut 60 (in an alternate asembly). The bolt head 56 is conveniently formed with a slot 62 for rotation by a screw driver (not shown) or analogous tool so that, thenut 46 being held against turning by its position within the opening 34, the respective nut 46 and washer 44 are drawn tight against opposite sides of therespective cone 16 and encircling-tube 18 by tightening the bolt within the nut. If desired, an internally threaded wing nut 60 can then be'mounted on the free end of the bolt 42 and screwed down against the nut 46 so as to serve as alock nut (FIGURE 3).

An alternate assemblyof these same elements is to place the nut 46 in the same position upon the base plate 28 within the angular socket formed by the square opening 34, then insert the bolt 42 through it until the underface 54 of the bolt abuts against the nut. The washer 44 is then. placed over the free end of the bolt which projects from the other side of the tube, and the wing nut 60 is screwed down against its Rather than making the bolt head56 and abutting nut 46 in separate pieces, they may be unitary; that is, the bolt head may be square sided 56a, FIGURE 9 or correspond to any polygonal shape of the socket formed by the tube opening 34. In such case, the head need not be slotted since it would not be rotated'. If a separate nut is used in this arrangement, it

wing nut on the opposite end of the threaded bolt, in such case the bolt 42 being threaded for its entire length.

Thus it will be observed that due to the lateral elongation of the cone aperture 22, the inserted bolt 42 and attached tube 18 can be moved a certain distance (when not tightened) longitudinal to the cone, and the anchoring member 46 slides a corresponding amount in and out the opening 34 but without completely emerging therefrom. Accordingly, within this span, the bolt will be locked, primarily at the position wherein the cone 16 fits tight in the tube 18, secondly when the tube edge 38 engages the abutment shoulder 40, but thirdly (in the absence of both of these conditions) at the position of farthest insertion permitted by the bolt 42 within the aperture 22-even though the cone does not completely contact the entire inner perimeter of the tubular socketsince the direct engagement of the anchoring element 46 upon the attachment cone 16 draws it against the opposite inner side of the tube socket 18, against the outer face of which the opposing coupling element (56 or 69) seats. Thus a comparatively large range of adjustment is possible between an inexactly fitted handle and socket, whether such variation is initially present or comes about in the course of aging or use. Accordingly a new tool head can be quickly mounted on an old handle or vice versa. Thus if one part or another becomes unserviceable, the whole article need not now be discarded as is the case when the handle and work head are permanently connected; also, only one handle need be maintained for interchangeable use with a plurality of tool heads.

In addition to the initial advantage obtained from fitting a conical handle in a conical socket, the tight engagement is further secured by the provision of a perpendicular seat for each of the opposing locking elements carried by the respective ends of the bolt. And this advantage is not lost with the further feature of adjustability provided by the elongated aperture 22 which permits the anchoring element 46 to be simultaneously slid along the plate 28 and moved in and out of the corresponding aperture 22. While this construction has been found particularly effective in joining a wooden handle to a metallic tool shank, its use is not limited to units made of such materials. Likewise, although illustrated by its application to particular horticultural implements,

the present coupling assembly finds employment indetachably joining other units of whatever kind which carry a tubular socket and attachment plug insertable therein.

I claim:

1. In a coupling assembly consisting essentially of a transversely apertured, tubular socket member open at one end to receive a correspondingly shaped and transversely apertured, attachment end of a handle inserted therein and having locking means including a headed bolt adapted to be inserted jointly through the mutually aligned apertures of the handle and socket member, which bolt carries a fastening element on the free end thereof for detachably coupling together the inserted handle and socket member, the improvement wherein the socket and apertured attachment end of said handle are correspondingly conically shaped for frictional registration upon insertion, said socket being formed with its apertures comprising an opposing, dissimilar pair of longitudinally staggered, lateral openings, and said handle end is formed with its transverse bolt-carrying aperture, angularly directed and alignable with the respective staggered, lateral openings of the socket to receive said bolt jointly therethrough, said conical attachment end being shaped with a pair of angularly diverging walls forming a lateral notch, one of said walls being disposed transverse to and surrounding one end of said angular aperture and the other wall being upstanding therefrom, an anchoring element carried by said inserted bolt and held thereby with a transverse face disposed in frictional registration with a wall of said notch and being in such position partially projecting through an adjacent tube opening, the side edges of which opening are disposed in, juxtaposition with the respective sides of said element so as to restrain it from turning, said tubular socket member being formed with an opposite lateral opening adapted to receive the shaft of said bolt therethrough, and a locking element carried by the end of saidbolt opposite said anchoring element.

2. The coupling assembly of the preceding claim 1 wherein the head of said bolt comprises said anchoring element.

3. The coupling assembly of the preceding claim wherein said locking element comprises a slotted head of said bolt and said bolt is cylindrical and terminally threaded for screw threaded engagement with said anchoring element.

4. The coupling assembly of the preceding claim 3 which additionally, includes a second locking element threadedly mounted on said bolt in frictional registration with the outer face of said anchoring element.

5. The coupling assembly of the preceding claim 1 which additionally includes a wedge-shaped washer carried by said bolt and having .an arcuate underface disposed in registration with and generally corresponding to the conical curvature of the socket member around a lateral opening thereof, said washer being formed with a generally flat, outer engaging surface disposed substantially perpendicular to the axis of the bolt and in frictional juxtaposition with the adjacent contact surface of an element of said coupling assembly adapted to be tightened thereagainst.

6. The coupling assembly of the preceding claim 1 wherein said anchoring element is a square head of said bolt, and said handle attachment end is formed with said angular bolt-carrying aperture elongated relative to the handle axis, whereby the inserted bolt before tightening is transversely movable therein in unison with the tubular socket member in effecting a snug fit of the handle end in the socket.

'7. The coupling assembly of the preceding claim 1 wherein said wall of the handle notch supporting the anchoring element is disposed in a plane convergingly inclined toward the free end of the handle relative to a corresponding plane defined by the opposite end of said bolt-carrying aperture, thus jointly defining a wedge progressively resistant to Withdrawal of the locked handle from the socket.

8. The combination comprising: a longitudinal tool handle and a detachable tool head, one of which is formed with a conical attachment end and the other of which has a correspondingly shaped, conical socket member open at one end for reception of the attachment end snugly therein, said socket member being formed with an opposing, dissimilar pair of longitudinally staggered, lateral openings, said conical attachment end being formed with a transverse, angularly directed, bolt-receiving aperture elongated axially to the conical end, said conical end being shaped with a pair of angularly diverging walls forming a lateral notch, one of said walls being disposed transverse to and surrounding one end of said aperture so as to provide a slideway in the direction of elongation of the aperture and the other notch wall being upstanding therefrom, a terminally threaded, cylindrical bolt inserted jointly through said elongated aperture and throu h the aligned socket openings, a polygonal-sided anchoring element carried by said bolt in sliding registration with said slideway and partially projecting through an adjacent lateral opening of the socket member, the side edges of which opening are disposed in juxtaposition with the polygonal sides of said element so as to restrain it from turning, a locking element carried by the end of said bolt opposite said anchoring element, and a wedgeshaped washer carried by the end of the bolt distant to said anchoring element, said washer having an arcuate underface disposed in registration with and generally corresponding to the conical curvature of the socketmemher around the adjacent lateral opening thereof and hav-. ing a generally fiat, outer engaging surface disposed sub stantially perpendicular to the axis of the bolt for tightening thereagainst of a corresponding annular engaging surface carried by the bolt.

9. The combination of the preceding claim 8 which additionallyinclude's a wing nut carried by the free end of said bolt.

'10. The combination of the preceding claim 8 wherein said slideway is disposed in a plane convergingly inclined toward the free end of the handle relative to a corresponding plane defined by the opposite end of said bolt-carrying aperture, thus jointly defining a Wedge progressively resistant to Withdrawal of the locked handle from the socket.

11. The combination comprising: a longitudinal tool handle and a detachable tool head, one of which is formed with a conical attachment end and the other of which has a correspondingly shaped, conical socket member open at one end for reception of the attachment end snugly therein, said conical socket and attachment end being transversely apertured to receive a coupling bolt References Cited in the file of this patent UNITED STATES PATENTS 240,617 Smith et al. Apr. 26, 1881 265,605 Hood 1 Oct. 10, 1882 1,113,897 French Oct. 13, 1914 1,183,851 Bryan May 23, 1916 1,387,127 Church Aug. 9, 1921 Greider May 2, 1933 

